Fuel injection system



My 17, 1960 K. PAULE ETAL 2,936,744

FUEL INJECTION SYSTEM 2 Sheets-Sheet 1 Filed NOV. 26, 1958 Fig] May 17, 1960 K. PAULE ET AL 2,936,744

' FUEL INJECTION SYSTEM Filed Nov. 26, 1958 l 2 Sheets-Sheet 2 M (mm3) 1000 2000 3000 (u/mfn) 1N VEN 10 R 5 2,936,744 FUEL INJEcrroN sYsrEM Kurt Paule, Stuttgart-Oberturkheim, and Heinrich Knapp,A Y

Stuttgart, Germany, assignors to Robert Bosch G.m.b.I-I., Stuttgart, vGermany Application November 26, 1958, Serial No. .776,608.1 Claims priority, applicationGermany November 27; 1957 l s claims. (ci. 12a-s2) The present invention refers to fuel injection systems for internal combustion engines operated by an external ignition control device, particularly to such systems related to motor cars. More specifically thepresent invenf tion concerns a fuel injection system ink which the fuel injection'rate is determined Vby .control means which :are timed during the engine.

In fuel injection systems of this type the fuel injection rate must be regulated depending upon thevarying rotational speeds of the internal combustion engine in such a manner that the fuel-air mixture entering the cylinder always contains sutlicient component of fuel. This fuel component must be kept inthe stoichiometric proportion with respect to the introduced air. e

It is therefore a mainobject of the present invention to provide for a speed-responsive fuel injection system operation by the actual rotational speed of for engines ofthe above described type,ycapab1e of automatically regulating the fuel injection rate in the above mentioned manner. Y' Y It is another object of this invention to provide 'for' a fuel injection system of the type set forth above, directly oper-ated and controlled by theconventional ignition control device'of the engine.

It is another object of this invention to provide a speedresponsive fuel injection system of the type setforth, controlled by the air supply control meanslof the engine or motor vehicle, which usually is a pedal-controlled choke so that the fuel injection rate is always correlated with the varying operating conditions of the engine. With above objects in view the fuel injection system according to the invention mainly comprises timing means adapted to be actua-ted by the ignitioncontrol' device of the internal combustion engine for producing a sequence of electrical pulses in synchronism with the operational frequency of the ignition control device so that the number of said electrical pulses is proportional to the Vrota tional speed of the engine, said timingmeans including electrical means capable ofconverting Vsaid pulses into a cont-rol potential, the average value of which isfproportionate to the operational frequency of said ignition control device. The system further includes electrically controllablefuel injection means adapted to be controlled by the above mentioned control potential of said elec- 1trical means in such a manner thatthe injection admisthe varying time intervals between the pulses permitting 2,936,744 APatented May V17,` 1960 lee i 2 amore or less substantial discharge of said capacitor assumes an average value which is proportionate to the operational frequency of the ignition control device.

v'The novel features which` are considered as characteristic for the'invention are set forth in particular in the appended claims. The invention itself/however, both as to its construction and its method ofv operation, together with additional objects and advantages thereof, will be best understood from the following description of specific-j embodiments when read in connection with the accompanying drawings, in which:

Figure 1 is a schematic diagram of an embodiment of the fuel injection system according to the invention, show. ing a circuit diagram vof the component electricalv parts and in connection therewith a four-cylinder internal coml bustion engine of the spark-ignition type, including diagrammatically the ignition control means and at fuel injection device;

`Figure 2 is a graph with time as abscissa and voltage as ordinate to illustrate the operation of the device; and l Figure 3 is a graph with revolutions per minute as abscissa and volume of fuel injection as ordinate, to illustrate the relation between these two factors and the different possible degrees of choke openings.

Referring now to Fig. l, the engine 10 includes a distributor shaft 11 which is not illustrated as such but represented by a dash-dot line which branches off into several arms only in order to show the connection between the engine 10 and. various elements in the diagram which are to be understood to berotated` by theengine10. The

distributors-haft 11 of the high voltage ignition device',

rotates at a rotational'speed equal to that of the cam shaft of the engine. Theshaft 11 carries a rotating distributor electrode 12 vwhich cooperates with four stationary electrodes 13, '14, 15 and 16; Each one ofthese last mentioned electrodes is connected by a cable to one of the spark plugs 17 of the engine 10. In order not to crowd the drawing, only the one cable 18 leading from theelectrode 13 to one of the spark plugs 17 is shown in Figure 1.

In circuit with. a source of energy consisting of a 12 voltbattery 20, is connected the primary coil 21 of an ignition coil which carries on a common iron corev 22 asecondary high voltage coil 24- which is also connected in circuit with the battery 20. Current from the battery isapplied to the primary winding 21 every time when an interrupter cam 25 also mounted on shaft 11 urges the interruptorV switch arm 26 against its stationary contact- 27 vsolas to'connect the second endof the primary winding 2,71 with the grounded minus connection of the battery V20. v Every time when the interrupter arm 26 under the action of a spring, not shown, separates from the stationary contact 27 and thereby interrupts the battery current owing through the primary winding 21 of the ignition coil, an ignition voltage is induced in the high voltage winding 24 which is connected with the rotating xdistributor electrode so that this ignition voltage is transmitted to the spa-rk plugs 17 Vin sequence corresponding'to the various positions of the electrode 12 with re-I within a solenoid coil 34. Whenever and as long as acur- The valve cone 35 is conv nected with an armature member 36 located movably aanwas Y rent J furnished by electronic amplier means 28 iiows through the solenoid coil 34 in a strength suicient for lifting the armature 36 and consequently the valve cone 35 from its valve seat, fuel is able to flow from the chamber 33 through the nozzle 32 into they air intake pipe 30 for producing the required fuel-.air mixture. The longer the valve cone 35 is lifted from its seat, the more fuelrwill flow from the fuel injection control means into the 'air intake pipe 30.

The fuel injection valve is opened, as will be explained further below, every time when a control cam 38 mounted on the same shaft 11 as the interrupter cam 25 closes the switch 39. However, the duration of 4the period through which the fuel injection valve remains open and thus the j amount of fuel injected in every cycle Yof its operation is regulated depending upon the varying operating conditions r condition. In the present case the dip-dop device serves Y the purpose of furnishing in its unstable condition a current impulse to the solenoid coil 34 of the injection control means causing the valve35 to open and to stay open, but permits the closing of -the valve 35 by automatically returning to its stablel condition when the control impulse which has changed the dip-flop device to its unstable condition, is terminated. In other words, during *the time during whichfthe ip-ilop device is in its unstable Vcondition the injection valve 35 is open and the duration of the unstable condition of the flip-Hop device determines the duration of the open position of the injection valve V35 and thus the amount of fuel injected into the air pipe 30. As will be explained in detail below, the unstable condition of the flip-flop device can be only maintained until a condenser 58 forming part of the Hip-flop device and charged during the stable condition thereofis discharged. The time of discharge is determined by a series combination of resistors 59 and 60 connected in parallel with the condenser 58. The purpose of the time control device 41 consists in furnishing'a control potential which depends in its magnitude ,upon the varying rotational speeds of the engine and which determines or .at least influences the period of time through which the flip-flop device 40 remains in its unstable condition.

Both the flip-flop device 40 and the time control device 41 are connected on one side with a common supply lineY 42 which is connectedV to the positive terminal of the battery 20. A common ground connection 43 is connected to the negative terminal of the battery 20. The actuation of `the ip-op device in synchronism with the rotational speed ofthe engine is effected bythe above mentioned cam member 38 rotating with the distributor shaft 11 and by the switch 39 operated by l-the cam 38 and connected in series combination with a resistor 51 of e.g. 20,000 ohm between the positive line 42 and the grounded negative line 43. A coupling Ycondenser 52 is connected to a junction point P3 between the switch 39 and the resistor 51 and is connected on the other side with a resistor 53 and a germanium diode 54. The other terminal of the diode 54 is connected with the base of a transistor T1 forming also a part of the tlip-lop device 4t). The base of this transistor is also connected byV a resistor 55 of e.g. 5,000 ohm with the positive iine 42, and at the same time by a resistor 56 via junction point P2 with the collector K2 of another transistor T2 of the Hip-flop device 40. The just mentioned'collector K2 of the transistor T2 is connected via junction point P2 'and a resistor 67 of e.g. 5,000 ohm with the grounded line 43. The emitter E2 'of the transistor T2 is connected with the sliding tap of a potentiometer R which in turn is connected at one end with the positive line 42 and with its other end with the emitter E3 of a transistor T3 which belongs to the time control device 41.

The time limitelement of the flip-flop device 40 comprises the above mentioned condenser 58 and the series combination of resistorsV 59 yand 60 and is connected in circuit between the junction point Pi and the base of the transistor T2, the junction point P1 being located between two resistors V61 and 62. The resistor 61 has e`.g. a value of 5,000 ohm and is connected to the grounded line 43 While the; resistor 62 has e.g. only a value of 1,200 ohm and is connected 'with the collector K1 of the transistor T1. Finallyga resistor 63 of e.g. 5,000 ohm is connected between the ground line 43 and the emitter El of the transistor T1, and an emitter resistor 64 or e.g. 500 ohm is connected with the positive line 42. Y

Of the two resistors forming part of the time limit of the flip-flop device 40, the resistor 59 is preferably variable depending upon the prevailing pressure and temperature offthe surrounding air by means of e.g. a diaphragm device59 as shown diagrammatically being connected with Vthe controlv member 59, while the other rresistor isv a fixed resistor. Assuming that thecondenser 58 has a capacity of 0.1 nf., the total series resistance of the vtwo resistors 59 and 60 should not exceed a value of 150,000 ohm.

The connection between `the base of the transistor T2 and the junction point P4 between the resistor 60 and one terminal of the condenser 58, includes a resistor 65 of e`.g; 5,000 ohm which is only shown because it favorably inuences the operation of the flip-op device Without being absolutely necessary.

An amplilier transistor 28 is connected with its base via junction point P2 withthe collector K2 vof the transistor T2. The emitter E28 of the transistor 28 is directly connected with the positive line 42 while the collector K28 is connected with one end of the solenoid coil 34 of the injection control device. The other end of the coil 34 is connected to ground and thereby to the negative terminal of the battery 20. j

The time control device 41 includes, in addition to the above mentioned transistor T3, a silicon diode 75 which is connected between the positive line 42 and the base Vof fthe transistor T3. This base is also connected across a diie'rentiating timing network composed of a coupling condenser 76 of e.g. approximately 100 micrornicroarad and an attenuating resistor 77 of e.g. 20,000V ohm, with the primary winding 21 of the ignition coil. While the emitter electrode E3; of the transistor T3 is connected with a charging'condenser 78 of eg. 200 nf.y which is connected, inV parallel with the potentiometer R, with the line 42. Thus the above mentioned diode 75 is connected in parallel with the transistor T3 and the charging condenser 78. -It can be seen, that whenever the switch arm 26 of the interruptor device is urged by the interrupter cam 2S 'against the stationary contact 27, the coupling condenser'76is charged 'via the emitter-base circuit of the transistor T3 by the pulses originatinglin the primary Winding 21 ofthe ignition coil. Each ofrthese pulses causes the transistor T3 to become conductive for a period of time which is determined by the charging time constant f the 'engine rotates because in this case the time availalxleV fordischarging becomes shorter.

AThe 'sliding tap of the-potentiometer R is operatively the potentiometer 1R in conjunction with the operation ofthe choke80. Therefore, the greater. the degree of opening of the choke 80, the more the sliding-.tap is moved toward the line,42, and the smaller is the portion of the charge potential of the charging condenser 78 which is applied to the emitter E2 of the transistor T2.

On the other hand, when choke 80 is only slightlylopened, eg. ca -2.5,", then the sliding tap is positioned near the opposite end of the potentiometer R so thatpractically the f ullcharge potential of the condenser 78 is applied to theiemitterr yE2 ofV the transistor T2. Thishas the eiect that the voltage appearing between the emitter E2 and the grounded line 43 is smaller than the full battery voltage. This is due to the fact that the potential of the .emitter E3 and therefore also the potential ofthe emitter E2 becomes smaller than the potential of-the positive line 42 as soon vas the voltage tapped off ofthe potentiom-` feter R'fand acting in opposition yto the'battelry voltage, has ;a value which is above the value 0. Hence the average .-.char'ge`"potent`ia1 of the condenser 78 increases with in- Uereasing rotational speed ofthe engine, the emitter-base current owing through the transistor T2 and through the resistors 65, 60,v 59and 61 decreases with increasing ro- :tational speed of the engine, -as long as the transistor T1 ishon-conductive. Thus, the potential UL of the cont-dens'er 58 will always decrease` with increasing rotational l:speed lof the engine. e

`It should be noted that in the circuit'illustrated by IFigure 1 the transistors T1, T2, and 28 are coupled conf'secutively with each other in such a manner thatv each :transistor isconnected'with the collector of the preceding transistor so that each followingtransistor is always n opposite conductive condition ascompared with the condition of the preceding transistor. Y Y j AIn practice, the ip-'op device 40 operates as follows: 'lAs long asv the switch 39 is in open position thewtransistor T1 is non-conductive 'while the transistor T2 Lis conductive'.Y YThis will be understood by considering that, under the assumption 'of the above given values of 1resistances and voltages, the collector potential k2 of the transistor T2 is approximately 10 volt. Under the same assumption the base potential of the transistor T1, deter?l minedby the resistors 55 and 56, has the value b1=1l.3 volts'. The emitter potential of the transistorTl, determined by the resistors 63 and 64, amounts to ye1=l0.9

volts. Since now the potential b1 is 'higher than thel emitter potential 1 no control current can'ow from the emitter to the base of the transistorY T1. yThus the transistor T1 is non-conductive. l

Under these circumstances the potential p1 at the junc# tion point P1 then depends practically only on that voltf `age drop which is caused in the resistor 61 bythe base current of the transistor T2 owing from. that lbase through the resistors 65, 60,59'ancl 61.v If it is now asv sinned that for a certain rotational speed of the engine and for the positionofthe sliding tap of the potentiometer R as shown in Figure l the emitter potential e2 ofthe :transistorrTZ is at least temporarily approximately constarit in the amount of ll volts, then the base potential b2 Iof the transistor T2 is approximately 10 volts. -Assuming further that the xed resistor 60 has 40,000 'ohms and at (the given moment the resistance adjusted at the air pres- .sure controlled resistor 59 'is'15,000ohms thenthe voltage drop appearing across the resistors 60 `and 59 4is approxi- `6 transistor T1 is lowered temporarily for fav-short period, approximately to 0 because in this instance the coupling condenser 5 2 is discharged and constitutesY at the moment of the closure of theswitch 39 practically a short circuit. Only now a control current can ow from the emitter E1 of the `transistor Tllto its base so Aas to make this transistor T1 so strongly conductive that its collector current 1K1 becomes about 1.8 ma. and causes across the resistor 61 a voltage drop of approximately 9 volts.. Consequently, the potential p1 at the junction point P1 which is connected with the now charged condenser 58, rises to a value of 9 volts. Since thecondenser 58 has its fullY charge potential UL the eiect of the started collector current Im of the transistor T1 is that the potential b2 at thebase of the transistor T2 is raised by the addition of the above mentioned voltage drop of 9 volts across the resistor 61l to a new potential of 17 volts. This potential isl under all circumstances above the emitter potenti-a1 e2 of the transistor T2. However, the transistor T2 can only carry current if and asv longas its base potential is lower than its emitter potential. Thus, the closingr of, the switch 39 causes the transistor T2 to be temporarily nonconductive so that' no emitter-base current can ow any longer. rThe collector potentialk?. now amounts to 3 volts which potential is' practically determined only by the current owing through the resistor 55, 56 and 67. Forthe reasons stated, after the time t1 no charge can be applied to the condenser 58 Via the resistor 65. Therefore, the condenser 58 is discharged comparatively quickly via the two resistors 60 and 59. To the extent as the condenser 58A discharges, and as its potential UL decreases, also the potential at the base of the transistor drop-s gradually to a value below the emitter potential e2 as can be seen in Figure 2. This condition is established at the time t2 whereafter thetransistor T2 is again capable to cause the ilow of a current through the resistor 67 whereby the potential of the junction point P2 is caused to'become substantially positive so that the transistor T1 and consequently the transistor 28 are suddenly rendered non-conductive. l

Returning once more to the above described performance, the current flowing through the resistors 55, S6 and 67 which determined the collector potential k2 of 3 volts, produces at the resistor'55 rconnected between the line 42 and the lbase of the transistor T1 a base potential b1- of 9 volts which issuiciently low in comparison to the emitter. potential e1 of 10.9 volts for maintaining the transistor T1 inconductive condition evenl at the time when the switch 39 is again in open condition Iand the impulse passing through theVv meanwhile charged coupling condenser 52 has terminated. v s

It can be seen that the flip-flop device 40 does not return to its original stable condition before the conacross the resistor 67. Hereby, as stated above, the po' tential at the junction point P2 becomes suliiciently posimately 8.3vvo lts while apotential p1 of 0.8 volt appears e i a'tthefjunction' point P1. Consequently, the'condenser 58 is charged to a potentiallof 8.3 volts as long as the switch 39 is open and the transistor T1 is thereforenonconductive. Y Y -tz'fA's soon las the camrmember 38 at the time t1 (see Fig. 2) closed by the cam member 38 moving the switch .39 into-itsrclosed position, the base potential blfof the tive for causing both the transistor T1 andthe transistor: 28 to become non-conductive. from. the diagram, the energizing current l for thesolenoid coil 34 is cut oit so that the injection valve 35 closes. Consequently, the duration of injection of -fuel through the nozzle 32 is limited between the times t1 and t2, as

shown clearly in Figure 2. vReferring now to Figure 3 it can be seen that the amount M of fuel injected. per cycle of the engine must be regulated in a mannerde pending'upon the number of revolutions n of the engine,

andalsoi depending upon the opening angle a of the choke shown in FigureV 1. It can be seen fromz-the Hereby, as can be seen"V gfaph of Fig. 3 `that for instanceV in the case of an 'angle tically unchanged over the entire speed range of the engine and amounts to approximately 48 A performance conforming with curves shot-vn in Figure `3 is obtained by the control device 41 because the sliding tap of the potentiometer is so connected opera- Vtively with the foot pedal 8l that, as mentioned above,

the'sliding tap is moved together with the turning of the foot pedal 81 in counterclockwise direction as seen in Figure l, in such a manner that the tap moves toward that end of the potentiometer which is connected with the line 42. On the other hand Whenever the pedal Si returns under the action of a yreturn spring not shown, into its position corresponding to idling of the engine, the tap is moved towards the/'other end of the potentiometer which is connected with the emitter E3 of the transistor TS.-

Since the average charge potential of the charging condenser 78 increases with increasing rotational speed of the engine, the emitter potential of the transistor T2 rises simultaneously so that the charging potential built up at the condenser 58 during the intervals between the consecutive changes of condition of the dip-flop device, decreases accordingly. lf in this manner the charge potential of the condenser 58 is reduced to a value Un then the second curve marked b2 in Figure 2 applies to this condition. The reduced charge Vpotential Un causes the base potential b2 of ythe transistor T2 to drop earlier to a value at which the transistor T2 cannot be kept any longer in its non-conductive condition, but on'the contrary, becomes conductive and therefore causes the injection valve 35 to close substantially earlier. The moment when this condition is obtained is marked in Fig. 2 3S t3.

It can be seen thereforethat as long as the sliding tap of the potentiometer R is kept by the corresponding position of the pedal 81 in a position in which a substantial portion of the charge potential of the condenser 78 is tapped olf the potentiometer R the amount of fuel M injected per cycle drops off with increasing rotational speed ofthe engine in conformity with illustration thereof in Fig. 3. However, when the choke plate 80 is in completelylopen position then the sliding tap will be positioned sovclose to the potentiometer end'YR' near the positive line 42 that practicallyno potential at all iis tapped olf the potentiometer R. Then the duration of the open'position of the injection valve is then practically independent of changes of the speed or number of revolutions of the engine.

lIt will be understood that each of the elements described above, or two orvmore together, may also find a useful application in other Vtypes `of fuel injection systems differing from the types described above.

While the invention has been illustrated and described as embodied in speed responsive fuel injection system for an internal combustion engine, it is not intended to Y be limited to the details shown, since various modifica` tions and structural changes may be made without departing in any way from the spirit of the present Vinvention. Y p

Without further analysis, the foregoing Will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various What is claimed as new and desired to be secured by Letters Patent is:

1. A speed-responsive fuel injection system for anV internal combustion engine having an ignition control device, comprising, in'combination, timingmeans'adapted to be actuated by the ignition control devicerof the internal combustion engine for producing a sequence of electrical pulses in synchronism with the operational frequency of said ignition control device so that the numberof said electrical pulses is proportional to the rrotational speed of said engine, said timing means including electrical means capable of converting said pulses into a control potential, the average value of which is proportionate to the operational frequency of the ignition control device; electrically controllable fuel injection 4means adapted to be controlled by said control potential of said electrical means in such a manner that the injection admission rate of said fuel injection means is determined by said control potential of-said electrical means; and actuating means in circuit with said electrically controllable fuel injection means and with said electrical means, whereby Asaid injection admission rate of said fuel'injectio'n meansis regulated in a predetermined proportion to the rotational speed of said internal combustion engine.

2. vA speed-responsive fuel injection system for an Iinterna-1 combustion engine having an ignition control device, comprising, in combination, timing means adapted to be Vactuated bythe ignition control device of the internal combustion engine for producing a sequence `of electrical pulses in synchronism with the operational frcqucncy of `said ignition control device so that the lnumber of said electrical pulses is proportional to the rotational Speed of said engine, said timing means including `capacitor means capable of being chargedby said pulses lto a charge potential, the ,average value of which is proportionate to the operationalV frequency of the ignition control device; electrically vcontrollable fuel injection means adapted to be controlled byjsaid charge potential of-said capacitor means in such a manner that the injection admission rate of said fuel injection means is determined by said charge potential of said capacitor means; and actuating means in circuit with said electrically controllable fuel injection means and with said capacitor means, whereby said injection admission rate of said fuel injection means is regulated in a predetermined proportion to the rotational speed of said internal combustion engine.

3. Aspeed-responsive fuel injection vsystem for an internal combustion engine operated by an external ignition control-device, comprising, in combination, asource ofrelectrical energy; timing means connected with said ignition control device for producing a Vsequence of pulses in synchronism With the operational frequency of said ignition control device, said timing-means including cacondition'in synchronism with said operational frequency of said ignition control device, and connected with said timing means for being returned to its stable condition after a time'interval depending upon Vsaid charge potential of said capacitor means; and electrically controllable fuel injection-means in circuit with said source of electrical energy and with said ipaflop means in suchfa manner that said fuel injection means is held in open position as long as said flip-flop means is in its unstable condition, .whereby the amount of fuel injected through said fuel injection means ,into said engine duringeach operational cycle is automatically regulated in a predetermined proportion-to the .rotational'speed of ,said Yinternal combustion engine. A

Y4.' :A .speed-responsive fuel injection system Yfor .an n- 9 ternal combustion engine operated by an external ignition control device, comprising, in combination, a source of electrical energy; rst timing means connected with lsaid ignition control device for producing a sequence of pulses in synchronism With-the operational frequency/of said ignition control'device and having a predetermined pulse f duration independent of variations of said operational frequency ofsaid ignition control device; second timing means connected to said first timing means and comprising transistor means and capacitor means in circuit with each other for converting said sequence of pulses into a charge potential of said capacitor increasing-with an increase of said operational frequency of said ignition control device; monostableip-flop means operatively connected with said ignition control device for being sequentially changed into its unstable condition in synchronism with said operational frequency of said ignition control device, and connected with said second timing means for being returned to its stable condition after a time interval depending Vupon said charge potential of said capacitor' means; and electricallycontrollable fuel :injec-l s tion means in circuit with vsaid source of electrical energy and with said flip-flop means in such a manner that said fuel injection means is held in open position as long as said ilip-flop means is in its unstable condition, whereby the amount of fuel injected through said fuel injection means during each operational cycle is automatically regulated in a predetermined proportion to the rotational speed of said internal combustion engine.

5. A speed-responsive fuel injection system for an internal combustion engine operated by an external ignition control device, comprising, in combination, a source `of electrical energy; first timing means connected with said ignition control device for producing a sequence of pulses in synchronism with the operational frequency of said ignition control device and having a predetermined pulse duration independent of variations of said operational frequency of said ignition control device; second timing means connected to said iirst timing means and comprising rst transistor means and capacitor means in circuit with each otherfor converting said sequence of pulses into a charge potential of said capacitor increasing with an increase of said operational frequency of said ignition control device; monostable ilip-op means'operatively connected with said ignition control device for being sequentially changed into its unstable condition in synchronism with said operational frequency of said ignition control device, and connected with said second timing means for being returned lto its stable condition after a time interval depending upon said charge potential of .said capacitor means, said hip-flop means including at least one second transistor and a sliding tap type potenti- -ometer connected in parallel with said capacitor means, the sliding tap of said potentiometer being connected with 'the control electrode of said second transistor so that a portion of said charge potential of said capacitor means Yis applied to said second transistor depending upon the :setting of said sliding tap along said potentiometer; and electrically controllable fuel injection means in circuit `with said source of electrical energy and with said flip- :rop means in such a manner that said fuel injection :means is held in open position as long as said nip-flop imeans is in its unstable condition, whereby the amount l1of fuel injected through said fuel injection means during leach operational cycle is automatically regulated in a predetermined proportion to the rotational speed oftsaid internal combustion engine.

6. A speed-responsive fuel injection system for an in- "ternal combustion engine operated by an external ignition control device, comprising, in combination, a source of electrical energy; rst timing means connected with said ignition control device for producing a sequence of pulses in synchronism with the operational frequency of said :ignition control device and having a predetermined pulse f duration independent of variations of said operational iiiaqueneyA of -said ignition sommi devicegsecnii timingl means connected to said first timing means and comprising first 'transistor' means `and capacitor means incir'cuit with each other for converting said sequence of pulses into' a charge potential of said capacitor increasing with an increase of saidoperational frequency of said ignition control device; monostable flip-flop means operativelyV connected with said ignition control device for being seportion of said charge potential of said capacitor means is :applied to said second transistor depending upon the setting of said sliding tap along said potentiometer;con trol means operatively connected with said sliding tap of saidpotentiometer and with the air supply control means in the engine, for causing said portion of said charge potential to increase in proportion with an increase of air supply effected by operation of said air supply control means, so as to correlate said portion of said chargepotential with the varying operating conditions of said engine; and electrically controllable fuel injection means in circuit with said source of electrical energy and with said flip-flop means in such a manner that said fuel injec tion means is held in open position as long as said flip-- ilop means is in its unstable condition, whereby thei amount of fuel injected through said fuel injection means during each operational cycle is automatically regulated in a predetermined proportion to the rotational speed of said internal combustion engine.

7. A speed-responsive fuel injection system for an internal combustion engine operated by anexternal ignition control device, comprising, in combination, a source of electrical energy; first timing means'connected with said ignition control device'for'producing a sequence of pulses in synchronism with the operational frequency of said ignition control device and having a predetermined pulse duration independent of variations of said operational frequency of said ignition control device; second timing means connected to said iirst timing means and comprising rst transistor means and capacitor means in circuit with each other for converting said sequence of pulses into a charge potential of said capacitor increasing with an increase of said operational frequency of said ignition control device; monostable flip-flop means operatively connected with said ignition control device for being se-l quentially changed into its unstable condition in syn chronism with said operational frequency of said ignition control device, and connected with saidsecond timing means for being returned to its stable condition after a time interval depending upon said charge potential of said capacitor means, said flip-nop means including at least one second transistor and a sliding tap type potenti ometer connected in parallel with said capacitor means, the sliding tap of said potentiometer being connected with the control electrode of said second transistor so that a portion of said charge potential of said capacitor means is applied to said second transistor depending uponthe setting of said sliding tap along said potentiometer; control means operatively connected with said sliding tap of said potentiometer and with the air supply controlt means of the engine, for causing said portion of said'. charge potential to increase in proportion with an in crease of air supply eiected by operation of said air' supply control means, so as to correlate said portion of` said charge potential with the varying operating condi-- tions of said engine; and electrically controllable fuel in-` jection means in circuit with said source of electrical."

energy and with saidoip-op means in sucha manner that said fuel injection means is held in open position as long as said ip-iiop means is-in itsl unstable condition; Y

transistor ampliiier means beingA connectedin said circuit between the output of said flip-flop means and said electrically controllable fuel injection means, for amplifying the current supplied by said source of energy through said flip-Hop means, whereby the amount of fuel injected through said fuel injection means during each operationalfcycle is automatically regulated in a predetermined proportion to the rotational speed of said internal combustion engine.

8. A speed-responsive fuel injection system for an intcrnal combustion engine operated by an external igni tion control device, comprising, in combination, a source of electrical energy; rst timing means connected with said ignition control device for producing a sequence of alternating positive and negative pulses in synchronism withfthe operational frequency of `said'ignition control device and having a predetermined pulse duration independent of variations of said operational frequency of said ignition control device; second timing means connected to said first timing means and comprising transistor means and capacitor means in circuit with each other 1.2 forconverting said sequence of pulses into a charge por. tential ofsaid capacitor increasing with an increase; ofI saidyoperational frequency'of said ignition control device, rectifierfmeans being connected in parallel withrsaid tran,-` sistor fand capacitor means, for short-circuiting every other one. of said alternating pulses; monostable flip-fiopv means operatively connected with said ignition control device for being sequentially changed into its'unstable condition in synchronism with said operational frequency of said' ignition control device, and connected with said second timing means for being .returned toits stable condition afterga time interval depending upon said chargei potential of said capacitor means; and electrically Vcon: trollable fuel injection means in circuit with said source of electricalV energy and with said flip-Hop means in such ar manner that said fuel injection means is held in open position as long as said iiip-op means is in its unstable-` condition, whereby the amount of fuel injected through` said fuel injection meansV during each operational cycle is automatically regulated in a predeterminedproportion: tothe rotational speed of said internal combustion engine. v

No references cited. 

